The costly pursuit of self-driving cars continues on. And on. And on.

New tests, in years of tests, revealed more and more distractions for the driverless cars. The wizards of Silicon Valley said people would be commuting to work in self-driving cars by now. Now the pursuit of autonomous cars is undergoing a reset. In 2015, the electric carmaker Tesla’s billionaire boss, Elon Musk, said fully functional self-driving cars were just two years away. Ferguson said many thought self-driving technology would improve like an internet service or a smartphone app.